Re: Re: CMedia 8738 - problems running Jack

[Dave Cunningham <spark@xdev.net>]

On Mon, Oct 24, 2005 at 02:55:23PM -0700, Mark Knecht wrote:
>On 10/24/05, Dave Cunningham <spark@xdev.net> wrote:
>> On Mon, Oct 24, 2005 at 09:32:24AM -0700, Mark Knecht wrote:
>> >On 10/24/05, Mark Knecht <markknecht@gmail.com> wrote:
>> >> Hi,
>> >>    I am unable to file any bug reports with the Alsa bug system so I'm
>> >> bringing the info here. Thanks in advance.
>> >>
>> >
>> >Thanks to James and Lee this is now files as bug # 1496
>> >
>> >https://85.132.177.35/alsa-bug/view.php?id=1496
>>
>>
>> I had and worked-around this problem, see
>>
>> http://boudicca.tux.org/hypermail/jackit-devel/this-month/0055.html
>>
>> i.e. run jack with the -o 2 parameter
>>
>
>Dave,
>   Thanks very much. This does allow Jack to run in duplex mode
>without crashing.

No probs, took me weeks to find a solution to this, I tried
every alsa version available on the site to find the point where
it broke, and then diffed the code before i figured that it
might be channel-related :)

>   Now, as things would have it, I cannot locate a cable to see if the
>beast makes noise. Off to the store to buy one I guess.
>
>   I'm not sure, in this case, how having more than 2 outputs would
>serve me. As far as I can tell the machine only has a stereo output
>jack. I have no idea where the other four would be used. Possibly
>other machines provide a 5.1 output?

Mine has plugs for front / rear / bass+centre, as well as
optical ports that i've never tried

heres a pic of something very similar from the net

http://www.microdirect.co.uk/ProductInfo.aspx?ProductID=8462

and here is lspci -v ouput

0000:03:04.0 Multimedia audio controller: C-Media Electronics
Inc CM8738 (rev 10)
        Subsystem: TERRATEC Electronic GmbH: Unknown device 1144
        Flags: bus master, medium devsel, latency 32, IRQ 18
        I/O ports at b000 [size=256]
        Capabilities: [c0] Power Management version 2


I imagine the issue is the number of cards that look very
similar but have different capabilities, and changing the driver
to add support for features of one kind of card will break
others...

It's also pretty confusing why sometimes there are several
stereo pcm devices to access different channels, and sometimes a
single pcm device with multiple alsa "channels".  Especially
since this confusion is presented to the user.


You should probably augment the bug report with a link to my
archived jackit-devel post and the work-around, and also provide
more information about exactly what kind of card you have.


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